Antibodies to paliperidone haptens and use thereof

ABSTRACT

Disclosed is an antibody which binds to paliperidone, which can be used to detect paliperidone in a sample such as in a competitive immunoassay method. The antibody can be used in a lateral flow assay device for point-of-care detection of paliperidone, including multiplex detection of aripiprazole, olanzapine, quetiapine, risperidone and paliperidone in a single lateral flow assay device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 13/971,387, filed Aug. 20, 2013, and published Feb. 27, 2014, as U.S. 2014/057297, and claims the benefit of U.S. Provisional Application Ser. No. 61/691,634, filed Aug. 21, 2012, the entire contents of each of which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of immunoassays, and in particular to antibodies that bind to paliperidone which can be used in immunoassays for detection of paliperidone.

BACKGROUND

Schizophrenia is a chronic and debilitating psychiatric disorder affecting approximately 0.45-1% of the world's population (van Os, J.; Kapur, S. “Schizophrenia” Lancet 2009, 374, 635-645). The principal goals of treatment are to achieve sustained remission from psychotic symptoms, reduce the risk and consequences of relapse, and improve patient functioning and overall quality of life. While many patients with schizophrenia are able to achieve symptom stability with the available antipsychotic medications, poor adherence to medication is a common reason for relapse with daily administered oral medications. Several studies (Abdel-Baki, A.; Ouellet-Plamondon, C.; Malla, A. “Pharmacotherapy Challenges in Patients with First-Episode Psychosis” Journal of Affective Disorders 2012, 138, S3-S14) investigating the outcomes of non-compliance have shown that patients with schizophrenia who do not take their medication as prescribed have higher rates of relapse, hospital admission and suicide as well as increased mortality. It is estimated that 40 to 75% of patients with schizophrenia have difficulty adhering to a daily oral treatment regimen (Lieberman, J. A.; Stroup, T. S.; McEvoy, J. P.; Swartz, M. S.; Rosenheck, R. A.; Perkins, D. O.; Keefe, R. S. E.; Davis, S. M.; Davis, C. E.; Lebowitz, B. D.; Severe, J.; Hsiao, J. K. “Effectiveness of Antipyschotic Drugs in Patients with Chronic Schizophrenia” New England Journal of Medicine 2005, 353(12), 1209-1223).

Therapeutic drug monitoring (TDM) is the quantification of serum or plasma concentrations of drugs, including anti-psychotic drugs, for treatment monitoring and optimization. Such monitoring permits, for example, the identification of patients that are not adhering to their medication regimen, that are not achieving therapeutic doses, that are non-responsive at therapeutic doses, that have suboptimal tolerability, that have pharmacokinetic drug-drug interactions, or that have abnormal metabolism resulting in inappropriate plasma concentrations. Considerable individual variability exists in the patient's ability to absorb, distribute, metabolize, and excrete anti-psychotic drugs. Such differences can be caused by concurrent disease, age, concomitant medication or genetic peculiarities. Different drug formulations can also influence the metabolism of anti-psychotic drugs. TDM permits dose optimization for individual patients, improving therapeutic and functional outcomes. TDM further permits a prescribing clinician to ensure compliance with prescribed dosages and achievement of effective serum concentrations.

To date, methods for determining the levels of serum or plasma concentrations of anti-psychotic drugs involve the use of liquid chromatography (LC) with UV or mass spectrometry detection, and radioimmunoassays (see, for example, Woestenborghs et al., 1990 “On the selectivity of some recently developed RIA's” in Methodological Surveys in Biochemistry and Analysis 20:241-246. Analysis of Drugs and Metabolites, Including Anti-infective Agents; Heykants et al., 1994 “The Pharmacokinetics of Risperidone in Humans: A Summary”, J Clin Psychiatry 55/5, suppl:13-17; Huang et al., 1993 “Pharmacokinetics of the novel anti-psychotic agent risperidone and the prolactin response in healthy subjects”, Clin Pharmacol Ther 54:257-268). Radioimmunoassays detect one or both of risperidone and paliperidone. Salamone et al. in U.S. Pat. No. 8,088,594 disclose a competitive immunoassay for risperidone using antibodies that detect both risperidone and paliperidone but not pharmacologically inactive metabolites. The antibodies used in the competitive immunoassay are developed against a particular immunogen. ID Labs Inc. (London, Ontario, Canada) markets an ELISA for olanzapine, another anti-psychotic drug, which also utilizes a competitive format. The Instructions For Use indicate that the assay is designed for screening purposes and intended for forensic or research use, and is specifically not intended for therapeutic use. The Instructions recommend that all positive samples should be confirmed with gas chromatography/mass spectrometry (GC-MS), and indicate that the antibody used detects olanzapine and clozapine (see ID Labs Inc., “Instructions For Use Data Sheet IDEL-F083”, Rev. Date Aug. 8, 2011). Some of these methods, namely HPLC and GC/MS, can be expensive and labor-intensive, and are generally only performed in large or specialty labs having the appropriate equipment.

A need exists for other methods for determining the levels of anti-psychotic drugs, particularly methods that can be performed in a prescribing clinician's office (where the treatment for an individual patient can be adjusted accordingly in a much more timely manner) and in other medical settings lacking LC or GC/MS equipment or requiring rapid test results.

Paliperidone is:

SUMMARY OF THE INVENTION

The present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula I and an immunogenic carrier: or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i).

wherein L¹ is OC(O)(CH₂)_(n), or (O)(CH₂)_(n); wherein n is 2, or 3;

L² is NHC(O),

or absent; L³ is (CH₂)_(m)CO₂H, or

wherein m is 0, 1, 2, or 3; provided that m may only be 0 if L² is absent.

Presently preferred embodiments of the antibody of the subject invention are the antibodies designated 5-5 and 5-9 generated against the compounds having Formula II and Formula III, and the antibody designated 2A-5 generated against the compound having Formula IV. Other suitable immunogens are the compounds having Formulas V and VI.

The antibodies of the subject invention can be provided in assay kits and assay devices, with a presently preferred device being a lateral flow assay device which provides for point-of-care analysis.

The invention further provides a method of producing an antibody which binds to paliperidone, the method comprising: (i) selecting a host cell for antibody production; and (ii) inoculating the host with a conjugate of a compound of Formula I and an immunogenic carrier, wherein the host produces an antibody which binds to paliperidone. Further provided is a method of producing a hybridoma cell line capable of producing a monoclonal antibody which binds to paliperidone. The method comprises: (i) selecting a host for antibody production; (ii) inoculating the host with a conjugate of a compound of Formula I and an immunogenic carrier; (iii) fusing a cell line from the inoculated host with a continuously dividing cell to create a fused cell capable of producing a monoclonal antibody which binds to paliperidone; and (iv) cloning the fused cell so as to obtain a hybridoma cell line.

The invention further provides a method of detecting paliperidone in a sample. The method comprises: (i) contacting a sample with an antibody according to the subject invention which is labeled with a detectable marker, wherein the labeled antibody and paliperidone present in the sample form a labeled complex; and (ii) detecting the labeled complex so as to detect paliperidone in the sample.

Further provided is a competitive immunoassay method for detecting paliperidone in a sample. The method comprises: (i) contacting a sample with an antibody according to the subject invention, and with paliperidone or a competitive binding partner of paliperidone, wherein one of the antibody and the paliperidone or competitive binding partner thereof is labeled with a detectable marker, and wherein sample paliperidone competes with the paliperidone or competitive binding partner thereof for binding to the antibody; and (ii) detecting the label so as to detect sample paliperidone.

Further objects, features and advantages of the present invention will be apparent to those skilled in the art from detailed consideration of the preferred embodiments that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 show Competitive ELISA results generated with hybridoma 5-9;

FIG. 3 shows Competitive ELISA results generated with risperidone/paliperidone clone 2A5;

FIG. 4 shows the competitive immunoassay format used on a lateral flow assay device;

FIG. 5 shows a typical dose response curve generated with risperidone/paliperidone clone 5-9;

FIG. 6 shows the chip design of a lateral flow assay device according to the subject invention;

FIG. 7 shows a typical dose response curve for an aripiprazole positive control generated with antibody 5C7 and a labeled aripiprazole competitive binding partner;

FIG. 8 shows a typical dose response curve for an olanzapine positive control generated with antibody 4G9-1 and a labeled olanzapine competitive binding partner;

FIG. 9 shows a typical dose response curve for a quetiapine positive control generated with antibody 11 and a labeled quetiapine competitive binding partner;

FIG. 10 shows a typical dose response curve for a risperidone positive control generated with antibody 5-9 and a labeled risperidone competitive binding partner;

FIG. 11 shows a typical dose response curve for a sample containing aripiprazole generated with aripiprazole antibody 5C7 in the presence of labeled aripiprazole competitive binding partner, with no dose response curve for olanzapine, quetiapine, or risperidone in the presence of a labeled competitive binding partner for each;

FIG. 12 shows a typical dose response curve for a sample containing olanzapine generated with olanzapine antibody 4G9-1 in the presence of a labeled olanzapine competitive binding partner, with no dose response curve for aripiprazole, quetiapine, or risperidone in the presence of a labeled competitive binding partner for each;

FIG. 13 shows a typical dose response curve for a sample containing quetiapine generated with quetiapine antibody 11 in the presence of a labeled quetiapine competitive binding partner, with no dose response curve for aripiprazole, olanzapine, or risperidone in the presence of a labeled competitive binding partner for each;

FIG. 14 shows a typical dose response curve for a sample containing risperidone generated with risperidone antibody 5-9 in the presence of a labeled risperidone competitive binding partner, with no dose response curve for aripiprazole, olanzapine, or quetiapine in the presence of a labeled competitive binding partner for each;

FIG. 15 shows a typical dose response curve for a sample containing aripiprazole generated with aripiprazole antibody 5C7 in the presence of a labeled aripiprazole competitive binding partner, with no dose response curve for olanzapine, quetiapine, or risperidone in the presence of antibody and labeled competitive binding partner for each;

FIG. 16 shows a typical dose response curve for a sample containing olanzapine generated with olanzapine antibody 4G9-1 in the presence of a labeled olanzapine competitive binding partner, with no dose response curve for aripiprazole, quetiapine, or risperidone in the presence of antibody and labeled competitive binding partner for each;

FIG. 17 shows a typical dose response curve for a sample containing quetiapine generated with quetiapine antibody 11 in the presence of labeled quetiapine competitive binding partner, with no dose response curve for aripiprazole, olanzapine, or risperidone in the presence of antibody and labeled competitive binding partner for each;

FIG. 18 shows a typical dose response curve for a sample containing risperidone generated with risperidone antibody 5-9 in the presence of a labeled risperidone competitive binding partner, with no dose response curve for aripiprazole, olanzapine, or quetiapine in the presence of antibody and labeled competitive binding partner for each;

FIG. 19 shows a comparison of the aripiprazole dose response curve generated as a positive control to the aripiprazole dose response curve generated in the multiplex format;

FIG. 20 shows a comparison of the olanzapine dose response curve generated as a positive control to the olanzapine dose response curve generated in the multiplex format;

FIG. 21 shows a comparison of the quetiapine dose response curve generated as a positive control to the quetiapine dose response curve generated in the multiplex format; and

FIG. 22 shows a comparison of the risperidone dose response curve generated as a positive control to the risperidone dose response curve generated in the multiplex format.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention provides an isolated antibody which binds to paliperidone. The invention further provides an assay kit and an assay device comprising the antibody. Also provided are methods of producing the antibody and of producing a hybridoma cell line capable of producing the antibody. Further provided is a method of detecting paliperidone in a sample, including a competitive immunoassay method.

In one embodiment, the present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula I and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i).

wherein L¹ is OC(O)(CH₂), or O(CH₂)_(n); wherein n is 2, or 3;

L² is NHC(O),

or absent; L³ is (CH₂)_(m)CO₂H, or

wherein m is 0, 1, 2, or 3; provided that m may only be 0 if L² is absent.

In a further embodiment, the present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula I and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i); wherein:

L¹ is OC(O)(CH₂)_(n), or O(CH₂)_(n); wherein n is 2, or 3;

L² is NHC(O),

or absent; L³ is (CH₂)_(m)CO₂H, or

wherein m is 0, 1, or 2; provided that m may only be 0 if L² is absent.

In a preferred embodiment, the present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula VII and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i).

In a preferred embodiment, the present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula VIII and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i).

In a preferred embodiment, the present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula IX and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i).

In a preferred embodiment, the present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula X and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i).

In a preferred embodiment, the present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula XI and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i).

Preferably, the antibody of the subject invention is generated in response to a conjugate of a compound selected from the compounds of: Formula I, Formula VII, Formula VIII, Formula IX, Formula X, and Formula XI; and an immunogenic carrier.

Further details of the compounds described by the formulas above and the conjugates formed by the compounds and an immunogenic carrier are provided in the section below entitled “Compounds, Conjugates and Immunogens”.

Further details of the antibodies of the subject invention are provided in the section below entitled “Antibodies”.

The subject invention further provides an assay kit comprising the antibody, as well as an assay device comprising the antibody. Preferably, the assay device is a lateral flow assay device. Further details of the assay kits and assay devices are provided below in the section entitled “Assay Kits and Devices”.

The invention further provides a method of producing an antibody which binds to paliperidone, the method comprising: (i) selecting a host cell for antibody production; and (ii) inoculating the host with a conjugate of a compound of Formula I and an immunogenic carrier, wherein the host produces an antibody which binds to paliperidone. In additional embodiments, the conjugate used in the method can be a conjugate of a compound selected from the compounds of: Formula VII, Formula VIII, Formula IX, Formula X, and Formula XI; and an immunogenic carrier. Further details on the production of the antibodies of the subject invention are provided in the section below entitled “Antibodies”.

Further provided is a method of producing a hybridoma cell line capable of producing a monoclonal antibody which binds to paliperidone. The method comprises: (i) selecting a host for antibody production; (ii) inoculating the host with a conjugate of a compound of Formula I and an immunogenic carrier; (iii) fusing a cell line from the inoculated host with a continuously dividing cell to create a fused cell capable of producing a monoclonal antibody which binds to paliperidone; and (iv) cloning the fused cell so as to obtain a hybridoma cell line. In additional embodiments, the conjugate used in the method can be a conjugate of a compound selected from the compounds of: Formula VII, Formula VIII, Formula IX, Formula X, and Formula XI; and an immunogenic carrier. Further details of the production of hybridomas in accordance with the subject invention are provided in the section below entitled “Antibodies”.

The invention further provides a method of detecting paliperidone in a sample. The method comprises: (i) contacting a sample with an antibody according to the subject invention which is labeled with a detectable marker, wherein the labeled antibody and paliperidone present in the sample form a labeled complex; and (ii) detecting the labeled complex so as to detect paliperidone in the sample. Further details of the method of detecting paliperidone in accordance with the subject invention are provided in the section below entitled “Immunoassays”.

Further provided is a competitive immunoassay method for detecting paliperidone in a sample. The method comprises: (i) contacting a sample with an antibody according to the subject invention, and with paliperidone or a competitive binding partner of paliperidone, wherein one of the antibody and the paliperidone or competitive binding partner thereof is labeled with a detectable marker, and wherein sample paliperidone competes with the paliperidone or competitive binding partner thereof for binding to the antibody; and (ii) detecting the label so as to detect sample paliperidone. Further details of the competitive immunoassay method of detecting paliperidone in accordance with the subject invention are provided in the section below entitled “Immunoassays”.

In a preferred embodiment of the subject invention, the detection of paliperidone is accompanied by the detection of one or more analytes in addition to paliperidone. Preferably the one or more analytes are anti-psychotic drugs other than paliperidone, and more preferably the anti-psychotic drugs other than paliperidone are selected from the group consisting of: aripiprazole, risperidone, quetiapine, olanzapine, and metabolites thereof.

As discussed above, the antibodies of the subject invention can be used in assays to detect the presence and/or amount of the anti-psychotic drug in patient samples. Such detection permits therapeutic drug monitoring enabling all of the benefits thereof. Detection of levels of anti-psychotic drugs may be useful for many purposes, each of which represents another embodiment of the subject invention, including: determination of patient adherence or compliance with prescribed therapy; use as a decision tool to determine whether a patient should be converted from an oral anti-psychotic regimen to a long-acting injectable anti-psychotic regimen; use as a decision tool to determine if the dose level or dosing interval of oral or injectable anti-psychotics should be increased or decreased to ensure attainment or maintenance of efficacious or safe drug levels; use as an aid in the initiation of anti-psychotic drug therapy by providing evidence of the attainment of minimum pK levels; use to determine bioequivalence of anti-psychotic drug in multiple formulations or from multiple sources; use to assess the impact of polypharmacy and potential drug-drug interactions; and use as an indication that a patient should be excluded from or included in a clinical trial and as an aid in the subsequent monitoring of adherence to clinical trial medication requirements.

Compounds, Conjugates and Immunogens

In relation to the compounds and conjugates and immunogens, the following abbreviations are used: AMAS is N-(α-maleimidoacetoxy) succinimide ester; Boc or BOC is tert-butoxycarbonyl; BTG is bovine thyroglobulin; Bu3N is tributylamine; DIEA is diisopropylethylamine; DCC is dicyclohexylcarbodiimide; DMF is N,N-dimethylformamide; KLH is keyhole limpet hemocyanin; SATA is N-succinimidyl S-acetylthioacetate; THF is tetrahydrofuran; TFA is trifluoroacetic acid; 18-Cr-6 is 18-Crown-6; Et3N is triethylamine; TBDMS is t-butyldimethylsilyl; DIC is diisopropylcarbodiimide; DMAP is N,N-dimethyl-4-aminopyridine; EDC is 1-ethyl-3(3-dimethylaminopropyl) carbodiimidehydrochloride; NHS is N-hydroxysuccinimide; TFP is Tetrafluorophenyl; PNP is p-nitrophenyl; TBTU is (O)-(Benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate; HOBT is N-Hydroxybenzotriazole; DEPBT is 3-(diethoxyphosphoryloxy)-1,2,3-benzotrazi-4(3H)-one; BOP-Cl is Bis(2-oxo-3-oxazolidinyl)phosphonic chloride; DTT is dithioerythritol.

The term “conjugate” refers to any substance formed from the joining together of separate parts. Representative conjugates include those formed by the joining together of a small molecule, such as the compounds of Formula I, and a large molecule, such as a carrier or a polyamine polymer, particularly a protein. In the conjugate the small molecule may be joined at one or more active sites on the large molecule.

The term “hapten” refers to a partial or incomplete antigen. A hapten is a protein-free substance, which is not capable of stimulating antibody formation, but which does react with antibodies. The antibodies are formed by coupling a hapten to a high molecular weight immunogenic carrier, and then injecting this coupled product, i.e., an immunogen, into a human or animal subject.

The term “immunogen” refers to a substance capable of eliciting, producing, or generating an immune response in an organism.

An “immunogenic carrier,” as used herein, is an immunogenic substance, commonly a protein, that can join at one or more positions with haptens, thereby enabling the production of antibodies that can bind with these haptens. Examples of immunogenic carrier substances include, but are not limited to, proteins, glycoproteins, complex polyamino-polysaccharides, particles, and nucleic acids that are recognized as foreign and thereby elicit an immunologic response from the host. The polyamino-polysaccharides may be prepared from polysaccharides using any of the conventional means known for this preparation.

Various protein types may be employed as immunogenic carriers, including without limitation, albumins, serum proteins, lipoproteins, etc. Illustrative proteins include bovine serum albumin, keyhole limpet hemocyanin, egg ovalbumin, bovine thyroglobulin, fraction V human serum albumin, rabbit albumin, pumpkin seed globulin, diphtheria toxoid, tetanus toxoid, botilinus toxin, succinylated proteins, and synthetic poly(aminoacids) such as polylysine.

Immunogenic carriers can also include poly amino-polysaccharides, which are a high molecular weight polymers built up by repeated condensations of monosaccharides. Examples of polysaccharides are starches, glycogen, cellulose, carbohydrate gums such as gum arabic, agar, and so forth. The polysaccharide also contains poly(amino acid) residues and/or lipid residues.

The immunogenic carrier can also be a poly(nucleic acid) either alone or conjugated to one of the above mentioned poly(amino acids) or polysaccharides.

The immunogenic carrier can also include solid particles. The particles are generally at least about 0.02 microns (μm) and not more than about 100 μm, and usually about 0.05 μm to 10 μm in diameter. The particle can be organic or inorganic, swellable or non-swellable, porous or non-porous, optimally of a density approximating water, generally from about 0.7 to 1.5 g/mL, and composed of material that can be transparent, partially transparent, or opaque. The particles can be biological materials such as cells and microorganisms, including non-limiting examples such as erythrocytes, leukocytes, lymphocytes, hybridomas, Streptococcus, Staphylococcus aureus, E. coli, and viruses. The particles can also be comprised of organic and inorganic polymers, liposomes, latex, phospholipid vesicles, or lipoproteins.

The term “derivative” refers to a chemical compound or molecule made from a parent compound by one or more chemical reactions.

The term “analogue” of a chemical compound refers to a chemical compound that contains a chain of carbon atoms and the same particular functional groups as a reference compound, but the carbon chain of the analogue is longer or shorter than that of the reference compound.

A “label,” “detector molecule,” “reporter” or “detectable marker” is any molecule which produces, or can be induced to produce, a detectable signal. The label can be conjugated to an analyte, immunogen, antibody, or to another molecule such as a receptor or a molecule that can bind to a receptor such as a ligand, particularly a hapten or antibody. A label can be attached directly or indirectly by means of a linking or bridging moiety. Non-limiting examples of labels include radioactive isotopes (e.g., ¹²⁵I), enzymes (e.g. β-galactosidase, peroxidase), enzyme fragments, enzyme substrates, enzyme inhibitors, coenzymes, catalysts, fluorophores (e.g., rhodamine, fluorescein isothiocyanate or FITC, or Dylight 649), dyes, chemiluminescers and luminescers (e.g., dioxetanes, luciferin), or sensitizers.

As used herein, a “spacer” refers to a portion of a chemical structure which connects two or more substructures such as haptens, carriers, immunogens, labels or binding partners through a functional linking group. These spacer groups are composed of the atoms typically present and assembled in ways typically found in organic compounds and so may be referred to as “organic spacing groups”. The chemical building blocks used to assemble the spacers will be described hereinafter in this application. Among the preferred spacers are straight or branched, saturated or unsaturated carbon chains. These carbon chains may also include one or more heteroatoms within the chain, one or more heteroatoms replacing one or more hydrogens of any carbon atom in the chain, or at the termini of the chains. By “heteroatoms” is meant atoms other than carbon which are chosen from the group consisting of oxygen, nitrogen, phosphorous and sulfur, wherein the nitrogen, phosphorous and sulfur atoms may exist in any oxidation state and may have carbon or other heteroatoms bonded to them. The spacer may also include cyclic or aromatic groups as part of the chain or as a substitution on one of the atoms in the chain.

The number of atoms in the spacing group is determined by counting the atoms other than hydrogen. The number of atoms in a chain within a spacing group is determined by counting the number of atoms other than hydrogen along the shortest route between the substructures being connected. Preferred chain lengths are between 1 to 20 atoms.

A “functional linking group” refers to a reactive group that is present on a hapten and may be used to provide an available reactive site through which the hapten portion may be coupled to another moiety through formation of a covalent chemical bond to produce a conjugate of a hapten with another moiety (such as a label or carrier). The hapten may be linked in this way to a moiety such as biotin to form a competitive binding partner.

Spacer groups may be used to link the hapten to the carrier. Spacers of different lengths allow one to attach the hapten with differing distances from the carrier for presentation to the immune system of the animal or human being immunized for optimization of the antibody formation process. Attachment to different positions in the hapten molecule allows the opportunity to present specific sites on the hapten to the immune system to influence antibody recognition. The spacer may contain hydrophilic solubilizing groups to make the hapten derivative more soluble in aqueous media. Examples of hydrophilic solubilizing groups include but are not limited to polyoxyalkyloxy groups, for example, polyethylene glycol chains; hydroxyl, carboxylate and sulfonate groups.

The term “nucleophilic group” or “nucleophile” refers to a species that donates an electron-pair to form a chemical bond in a reaction. The term “electrophilic group” or “electrophile” refers to a species that accepts an electron-pair from a nucleophile to form a chemical bond in a reaction.

The term “substituted” refers to substitution of an atom or group of atoms in place of a hydrogen atom on a carbon atom in any position on the parent molecule. Non limiting examples of substituents include halogen atoms, amino, hydroxy, carboxy, alkyl, aryl, heteroalkyl, heteroaryl, cyano, alkoxy, nitro, aldehyde and ketone groups.

The term “alkyl” refers to saturated or unsaturated linear and branched chain radicals of up to 12 carbon atoms, unless otherwise indicated, and is specifically intended to include radicals having any degree or level of saturation. Alkyl includes, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, isohexyl, heptyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl and dodecyl.

The term “cycloalkyl” refers to a saturated or partially unsaturated monocyclic or bicyclic hydrocarbon ring radical composed of from 3 to 10 carbon atoms. Alkyl substituents may optionally be present on the ring. Examples include cyclopropyl, 1,1-dimethyl cyclobutyl, 1,2,3-trimethylcyclopentyl, cyclohexyl and cyclohexenyl.

The term “heteroalkyl” refers to an alkyl group that includes one or more heteroatoms within the chain, one or more heteroatoms replacing one or more hydrogens of any carbon atom in the chain, or at termini of the chains.

The term “aminoalkyl” refers to at least one primary or secondary amino group bonded to any carbon atom along an alkyl chain.

The term “alkoxy” refers to straight or branched chain radicals of up to 12 carbon atoms, unless otherwise indicated, bonded to an oxygen atom. Examples include but are not limited to methoxy, ethoxy, propoxy, isopropoxy and butoxy.

The term “alkoxyalkyl” refers to at least one alkoxy group bonded to any carbon atom along an alkyl chain.

The term “thioalkyl” refers to at least one sulfur group bonded to any carbon atom along an alkyl chain. The sulfur group may be at any oxidation state and includes sulfoxides, sulfones and sulfates.

The term “carboxylate group” includes carboxylic acids and alkyl, cycloalkyl, aryl or aralkyl carboxylate esters.

The term “alkylcarbonyl” refers to a group that has a carbonyl group bonded to any carbon atom along an alkyl chain.

The term “heteroaryl” refers to 5- to 7-membered mono- or 8- to 10-membered bicyclic aromatic ring radicals, any ring of which may consist of from one to four heteroatoms selected from N, O or S where the nitrogen and sulfur atoms can exist in any allowed oxidation state. Examples include benzimidazolyl, benzothiazolyl, benzothienyl, benzoxazolyl, furyl, imidazolyl, isothiazolyl, isoxazolyl, oxazolyl, pyrazinyl, pyrazolyl, pyridyl, pyrimidinyl, pyrrolyl, quinolinyl, thiazolyl and thienyl.

The term “aryl” refers to monocyclic or bicyclic aromatic ring radicals containing from 6 to 12 carbons in the ring. Alkyl substituents may optionally be present on the ring. Examples include phenyl, biphenyl and napththalene.

The term “aralkyl” refers to a C₁₋₆ alkyl group containing an aryl substituent. Examples include benzyl, phenylethyl or 2-naphthylmethyl.

The term “acyl” refers to the group —C(O)R_(a), where R_(a) is hydrogen, alkyl, cycloalkyl, heteroalkyl, aryl, aralkyl and heteroaryl. An “acylating agent” adds the —C(O)R_(a) group to a molecule.

The term “sulfonyl” refers to the group —S(O)₂R_(b), where R_(b) is hydrogen, alkyl, cycloalkyl, heteroalkyl, haloalkyl, aryl, aralkyl and heteroaryl. A “sulfonylating agent” adds the —S(O)₂R_(a) group to a molecule.

Spacers bearing reactive functional linking groups for the attachment of haptens to carrier moieties may be prepared by a wide variety of methods. The spacer may be formed using a molecule that is differentially functionalized or activated with groups at either end to allow selective sequential reaction with the hapten and the carrier, but the same reactive moiety may also be used at both ends. The groups selected for reaction with the hapten and the functional linking group to be bound to the carrier are determined by the type of functionality on the hapten and the carrier that the hapten is to be bonded with. Spacers and methods of attachment to haptens and carriers include but are not limited to those described by Brinkley, M., A., Bioconjugate Chem. 1992, 3:2-13, Hermanson, Greg T., Bioconjugate Techniques, Academic Press, London, Amsterdam, Burlington, Mass., USA, 2008 and Thermo Scientific Pierce Crosslinking Technical Handbook; available for download or hard copy request from Thermo Scientific 3747 N Meridian Rd, Rockford, Ill. USA 61101, ph 800-874-3723 or at: http://www.piercenet.com/ and references within. Many differentially activated molecules for formation of spacer groups are commercially available from vendors, for example Thermo Scientific.

For haptens bearing an amino group, modes of attachment of the spacer to the hapten include reaction of the amine on the hapten with a spacer building block bearing an acyl halide or active ester. “Active esters” are defined as esters that undergo reaction with a nucleophilic group, for example an amino group, under mild conditions to form a stable linkage. A stable linkage is defined as one that remains intact under conditions of further use, for example subsequent synthetic steps, use as an immunogen, or in a biochemical assay. A preferred example of a stable linkage is an amide bond. Active esters and methods of formation are described by Benoiton, N. L., in Houben-Weyl, Methods of Organic Chemistry, Thieme Stuttgart, New York, vol E22 section 3.2:443 and Benoiton, N. L., Chemistry of Peptide Synthesis, Taylor and Francis, NY, 2006. Preferred active esters include p-nitrophenyl ester (PNP), N-hydroxysuccinimide ester (NHS) and tetrafluorophenyl ester (TFP). Acyl halides may be prepared by many methods known to one skilled in the art for example, reaction of the carboxylic acid with thionyl chloride or oxalyl chloride, see: Fieser, L. F. and Fieser, M. Reagents for Organic Synthesis, John Wiley and Sons, NY, 1967 and references within. These may be converted to other active esters such as p-nitrophenyl esters (PNP) which may also be used in active bi-functional spacers as described by Wu et. al, Organic Letters, 2004, 6 (24):4407. N-hydroxysuccinimide (NHS) esters may be prepared by reaction of N,N-disuccinimidyl carbonate (CAS 74124-79-1) with the carboxylic acid of a compound in the presence of an organic base such as triethylamine or diisopropylethylamine in an aprotic solvent under anhydrous conditions as described in Example 35 of WO2012012595 or by using N-hydroxysuccinimide and dicyclohexylcarbodiimide (DCC) or other dehydrating agent, under anhydrous conditions. Tetrafluorophenyl esters (TFP) may be prepared by reaction of carboxylic acids with 2,3,5,6-tetrafluorophenyltrifluoroacetate in the presence of an organic base such as triethylamine or diisopropylethylamine in an aprotic solvent under anhydrous conditions as reported by Wilbur, et. al, Bioconjugate Chem., 2004, 15(1):203. One skilled in the art will recognize that spacers shown in Table 1, among others, can be obtained using known methods and attached to amino-bearing haptens utilizing routine optimization of reaction conditions. These spacers allow attachment of the hapten to a thiol group on a carrier.

TABLE 1

Reasonable values for m and n are between 1 and 10

Direct coupling of the amine on the hapten and a carboxylic acid functionality on the spacer building block in the presence of a coupling agent may also be used as a mode of attachment. Preferred reagents are those typically used in peptide synthesis. Peptide coupling reagents include but are not limited to (O)-(Benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate (TBTU, CAS #125700-67-6), see: Pruhs, S., Org. Process. Res. Dev. 2006, 10:441; N-Hydroxybenzotriazole (HOBT, CAS #2592-95-2) with a carbodiimide dehydrating agent, for example N—N-dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), or 1-ethyl-3(3-dimethylaminopropyl)carbodiimidehydrochloride (EDC), see: König W., Geiger, R. Chem. Ber, 1970, 103 (3):788; 3-(diethoxyphosphoryloxy)-1,2,3-benzotrazin-4(3H)-one (DEPBT, CAS#165534-43-0), see: Liu, H. et. al., Chinese Chemical Letters, 2002, 13(7):601; Bis(2-oxo-3-oxazolidinyl)phosphonic chloride; (BOP-Cl, CAS#68641-49-6), see: Diago-Meseguer, J et. al. Synthesis, 1980, 7:547-51 and others described in detail by Benoiton in Chemistry of Peptide Synthesis, CRC Press, Boca Raton, Fla., 2005, Chapter 2, and the technical bulletin provided by Advanced Automated Peptide Protein Technologies (aapptec), 6309 Shepardsville Rd., Louisville Ky. 40228, ph 888 692 9111; www.aapptec.com, and references within. These methods create a stable amide linkage attaching the hapten to the spacer. Examples of spacers that can be obtained using known methods and attached to amino-bearing haptens utilizing routine optimization of reaction conditions employing the methods described and cited above are shown, but not limited to those in Table 2. These spacers allow attachment of the hapten to a thiol group on a carrier.

TABLE 2

reasonable range for n is between 1-10

Spacers may also be constructed in a step-wise fashion by sequential attachment of appropriate chemical groups to the hapten including the step of forming the functional linking group that is capable of binding to the carrier. See illustrative examples under General Reaction Schemes.

Additionally, when the hapten has a nucleophilic group, for example a thiol group, an amino group or a hydroxyl group which will become the point of attachment of the spacer, the spacer may also be constructed by alkylation of the thiol, amine or hydroxyl group. Any alkyl group that is appropriately substituted with a moiety capable of undergoing a substitution reaction, for example, an alkyl halide, or sulfonic acid ester such as p-Toluenesulfonate, may be used to attach the spacer. Many examples of alkylation reactions are known to one skilled in the art and specific examples may be found in the general chemical literature and optimized through routine experimentation. A discussion of alkylation reactions with many references can be found in Chapter 10 of March's Advanced Organic Chemistry, Smith, M. B., and March, J., John Wiley & sons, Inc. NY, 2001. Other linkages may also be employed such as reaction of the nucleophilic moiety, for example an amine, on the hapten with an isocyanate to form a urea or reaction with an isothiocyanate to form a thiourea linkage, see: Li, Z., et. al., Phosphorus, Sulfur and Silicon and the Related Elements, 2003, 178(2):293-297. Spacers may be attached to haptens bearing hydroxyl groups via reaction with isocyanate groups to form carbamate or urethane linkages. The spacer may be differentially activated with the isocyanate functional group on one end and a functional linking group capable of reacting with the carrier, see: Annunziato, M. E., Patel, U.S., Ranade, M. and Palumbo, P. S., Bioconjugate Chem., 1993, 4:212-218.

For haptens bearing a carboxylic acid group, modes of attachment of a spacer portion to the hapten include activation of the carboxylic acid group as an acyl halide or active ester, examples of which are shown in Table 3, preparation of which are described previously, followed by reaction with an amino (—NH₂—), hydrazino (—NH—NH₂—), hydrazido (—C(O)—NH—NH₂—) or hydroxyl group (—OH) on the spacer portion to form an amide, hydrazide, diacylhydrazine or ester linkage, or direct coupling of the carboxylic acid group with an amino group on the spacer portion or directly on the carrier with a peptide coupling reagent and/or carbodiimide dehydrating reagent, described previously, examples of which are shown in Tables 4 and 5. Procedures found in references cited previously for formation of activated esters and use of peptide coupling agents may be employed for attachment of carboxylic acid-bearing haptens to spacer building blocks and protein carriers with available amino groups utilizing routine optimization of reaction conditions.

TABLE 3

Sulfo NHS and NHS

TFP

Acyl chloride

PNP

TABLE 4

HOBT

DEPT

BOP-Cl

TBTU

TABLE 5

diisopropylcarbodiimide (DIC)

Dicyclohexylcarbodiimide (DCC)

1-ethyl-3(3- dimethylaminopropyl)carbodiimide•HCl (EDC)

Other electrophilic groups may be present on the hapten to attach the spacer, for example, a sulfonyl halide

or electrophilic phosphorous group, for example:

See: Malachowski, William P., Coward, James K., Journal of Organic Chemistry, 1994, 59 (25):7616

or:

R_(c) is alkyl, cycloalkyl, aryl, substituted aryl, aralkyl.

See: Aliouane, L., et. al, Tetrahedron Letters, 2011, 52(28):8681.

Haptens that bear aldehyde or ketone groups may be attached to spacers using methods including but not limited to reaction with a hydrazide group H₂N—NH—C(O)— on the spacer to form an acylhydrazone, see: Chamow, S. M., Kogan, T. P., Peers, D. H., Hastings, R. C., Byrn, R. A. and Askenaszi, A., J. Biol. Chem., 1992, 267(22): 15916. Examples of bifunctional hydrazide spacer groups that allow attachment to a thiol group on the carrier are shown in Table 6.

TABLE 6

Haptens may also contain thiol groups which may be reacted with the carrier provided that the carrier has been modified to provide a group that may react with the thiol. Carrier groups may be modified by methods including but not limited to attachment of a group containing a maleimide functional group by reaction of an amino group on the carrier with N-Succinimidyl maleimidoacetate, (AMAS, CAS #55750-61-3), Succinimidyl iodoacetate (CAS#151199-81-4), or any of the bifunctional spacer groups shown in Table 1 to introduce a group which may undergo a reaction resulting in attachment of the hapten to the carrier.

The functional linking group capable of forming a bond with the carrier may be any group capable of forming a stable linkage and may be reactive to a number of different groups on the carrier. The functional linking group may preferably react with an amino group, a carboxylic acid group or a thiol group on the carrier, or derivative thereof. Non-limiting examples of the functional linking group are a carboxylic acid group, acyl halide, active ester (as defined previously), isocyanate, isothiocyanate, alkyl halide, amino group, thiol group, maleimide group, acrylate group (H₂C═CH—C(O)—) or vinyl sulfone group H₂C═CH—SO₂—) See: Park, J. W., et. al., Bioconjugate Chem., 2012, 23(3): 350. The functional linking group may be present as part of a differentially activated spacer building block that may be reacted stepwise with the hapten and the resulting hapten derivative may then be reacted with the carrier. Alternatively, the hapten may be derivatized with a spacer that bears a precursor group that may be transformed into the functional linking group by a subsequent reaction. When the functional linking group on the spacer is an amine or a carboxylic acid group, the coupling reaction with the carboxylic acid group or amine on the carrier may be carried out directly through the use of peptide coupling reagents according to procedures in the references cited above for these reagents.

Particular disulfide groups, for example, pyridyldisulfides, may be used as the functional linking group on the spacer which may undergo exchange with a thiol group on the carrier to from a mixed disulfide linkage, see: Ghetie, V., et al., Bioconjugate Chem., 1990, 1:24-31. These spacers may be attached by reaction of the amine-bearing hapten with an active ester which is attached to a spacer bearing the pyridyldisulfide group, examples of which include but are not limited to those shown in Table 7.

TABLE 7

Most often the carrier is a protein and the ε-amino groups of the lysine residues may be used for attachment, either directly by reaction with an amine-reactive functional linking group or after derivitization with a thiol-containing group, including N-Succinimidyl S-Acetylthioacetate, (SATA, CAS 76931-93-6), or an analogue thereof, followed by cleavage of the actetate group with hydroxylamine to expose the thiol group for reaction with the functional linking group on the hapten. Thiol groups may also be introduced into the carrier by reduction of disulfide bonds within protein carriers with mild reducing reagents including but not limited to 2-mercaptoethylamine, see: Bilah, M., et. al., Bioelectrochemistry, 2010, 80(1):49, phosphine reagents, see: Kirley, T. L., Analytical Biochemistry, 1989, 180(2):231 or dithioerythritol (DTT, CAS 3483-12-3) Cleland, W., Biochemistry, 1964, 3:480-482.

General Reaction Schemes

Compounds useful for producing antibodies according to the subject invention can be synthesized in accordance with the general synthetic methods described below. Compounds of Formula (I) can be prepared by methods known to those who are skilled in the art. The following reaction schemes are only meant to represent examples of the invention and are in no way meant to be a limit of the invention.

Compounds of Formula I where L¹ is OC(O)(CH₂)_(n), L² is absent, and L³ is CO₂H may be made according to Scheme 1. Reaction of the hapten paliperidone proceeds with a cyclic anhydride compound, such as succinic anhydride or glutaric anhydride, in a solvent such as pyridine, at temperatures ranging from room temperature to 60° C., for about 48 hours.

Compounds of Formula I where L¹ is OC(O)(CH₂)_(n), L² is NHC(O), and L³ is

may be made according to Scheme 2. Condensation of a suitable boc-protected amino acid, such as glycine, with paliperidone is accomplished using a dehydrating agent such as dicyclohexylcarbodiimide. The reaction is carried out in an aprotic solvent, such as dichloromethane, at room temperature, using a base such as N,N-dimethyl-4-pyridinamine. Deprotection of the amine group proceeds with trifluoroacetic acid, flowed by subsequent addition of the maleimide functionality. The maleimide may be introduced by any method known in the art. For example, reaction with N-maleoyl-substituted alkyl amino acid (as shown in scheme 2) in a solvent such as dichlorormethane and coupling reagents such as diisopropylethylamine and diethyl cyanophosphonate gives the maleimide functionalized linker on the hapten. Alternatively, other maleimide functionalizing groups such as 2,5-dioxopyrrolidin-1-yl 2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)acetate may be used in a solvent such as DMF and a base, such as tributylamine.

The procedures of Scheme 2 may also be used for compounds of Formula I where L¹ is O(CH₂)_(n). Paliperidone is instead reacted with an appropriate boc-protected amino alkyl bromide (such as boc-aminopropyl bromide), 18-Crown-6, and sodium hydride, in a solvent such as THF, at about room temperature, for about 6 hours. Subsequent removal of the boc protecting group and installation of the maleimide functionality proceeds as described in Scheme 2.

Compounds of Formula I where L¹ is O(CH₂)_(n), L² is absent, and L³ is (CH₂)_(m)CO₂H may be made according to Scheme 3. Paliperidone is reacted with a CO₂H substituted alkyl bromide in a solvent, such as THF, in the presence of 18-Crown-6 and sodium hydride, for about 18 h.

Compounds of Formula I where L¹ is O(CH₂)_(n), L² is

and L³ is (CH₂)_(m)CO₂H may be made according to Scheme 4. Paliperidone functionalized with a linker and CO₂H, prepared as described in scheme 3, is treated with N-t-butoxycarbonylpiperazine, diethyl cyanophosphonate, and a base, such as diisopropylethylamine. The reaction is carried out in dichloromethane, for about 2 hours at room temperature. Deprotection of the piperazinyl group is accomplished with trifluoroacetic anhydride as described in Scheme 2, followed by reaction with an appropriate anhydride, such as succinic anhydride or maleic anhydride, in the presence of a suitable base such as diisopropylethylamine. Alternatively, one skilled in the art will recognize that the deprotected piperazinyl group may be elaborated with a maleimide functionality, as described in Scheme 2.

Maleimide functionalized haptens may be conjugated to proteins according to the method shown in Scheme 5. Activation of protein lysine residues by acylation of the epsilon-nitrogen with N-succinimidyl S-acetylthioacetate (SATA) followed by subsequent hydrolysis of the S-acetyl group with hydroxylamine produces a nucleophilic sulfhydryl group. Conjugation of the sulfhydryl activated protein with the maleimide derivatized hapten (prepared as described in general Scheme 2) proceeds via a Michael addition reaction. Suitable proteins are known to those skilled in the art and include keyhole limpet hemocyanin, bovine thyroglobulin, and ovalbumin.

Carboxylic acid functionalized haptens may be conjugated to proteins according to the method shown in Scheme 6. Reaction with N-hydroxysuccinimide and a suitable coupling agent, such as dicyclohexylcarbodiimide, and a base, such as tributyl amine, in a solvent such as DMF, at a temperature of about 20° C., for about 18 hrs activates the carboxylic acid with the leaving group. The activated linker and hapten may then be conjugated to a protein in a solvent, such as a pH 7.5 phosphate buffer, at about 20° C., for about 2.5 hours. Suitable proteins are known to those skilled in the art and include keyhole limpet hemocyanin, bovine thyroglobulin, and ovalbumin.

Antibodies

The present invention is directed to an isolated antibody or a binding fragment thereof, which binds to paliperidone and which: (i) is generated in response to a conjugate of a compound of Formula I and an immunogenic carrier; or (ii) competes for an epitope which is the same as an epitope bound by the antibody of (i). The term “antibody” refers to a specific protein capable of binding an antigen or portion thereof (in accordance with this invention, capable of binding to an anti-psychotic drug or metabolite thereof). An antibody is produced in response to an immunogen which may have been introduced into a host, e.g., an animal or a human, by injection. The generic term “antibody” includes polyclonal antibodies, monoclonal antibodies, and antibody fragments.

“Antibody” or “antigen-binding antibody fragment” refers to an intact antibody, or a fragment thereof, that competes with the intact antibody for binding. Generally speaking, an antibody or antigen-binding antibody fragment, is said to specifically bind an antigen when the dissociation constant is less than or equal to 1 μM, preferably less than or equal to 100 nM and most preferably less than or equal to 10 nM. Binding can be measured by methods know to those skilled in the art, an example being the use of a BIAcore™ instrument.

Antibody fragments comprise a portion of an intact antibody, preferably the antigen binding or variable region of the intact antibody. Binding fragments include Fab, Fab′, F(ab′)₂, and Fv fragments; diabodies; linear antibodies; single-chain antibody molecules; and multispecific antibodies formed from antibody fragments. An antibody other than a “bispecific” or “bifunctional” antibody is understood to have each of its binding sites identical.

As used herein, “epitope” includes any protein determinant capable of specific binding to an immunoglobulin or T-cell receptor. Epitopic determinants usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and usually have specific three dimensional structural characteristics, as well as specific charge characteristics. Two antibodies are said to “bind the same epitope” if one antibody is shown to compete with the second antibody in a competitive binding assay, by any of the methods well known to those skilled in the art (such as the BIAcore™ method referred to above). In reference to a hapten (such as paliperidone or other anti-psychotic drug), an antibody can be generated against the non-antigenic hapten molecule by conjugating the hapten to an immunogenic carrier. An antibody is then generated which recognizes an “epitope” defined by the hapten.

“Isolated” when used in the context of an antibody means altered “by the hand of man” from any natural state; i.e., that, if it occurs in nature, it has been changed or removed from its original environment, or both. For example, a naturally occurring antibody naturally present in a living animal in its natural state is not “isolated”, but the same antibody separated from the coexisting materials of its natural state is “isolated”, as the term is employed herein. Antibodies may occur in a composition, such as an immunoassay reagent, which are not naturally occurring compositions, and therein remain isolated antibodies within the meaning of that term as it is employed herein.

“Cross-reactivity” refers to the reaction of an antibody with an antigen that was not used to induce that antibody.

Preferably, the antibody of the subject invention will bind to the drug and any desired pharmacologically active metabolites. By altering the location of the attachment of the immunogenic carrier to the compounds of the invention, selectivity and cross-reactivity with metabolites can be engineered into the antibodies. For paliperidone (9-hydroxyrisperidone), cross-reactivity with risperidone or other risperidone metabolites such as 7-hydroxyrisperidone and N-dealkylrisperidone may or may not be desirable. An antibody that cross-reacts with risperidone and paliperidone may be desirable, which does not react with 7-hydroxyrisperidone or N-dealkylrisperidone, thus detecting risperidone and its major pharmacologically active metabolite paliperidone. Alternatively, it may be desirable to detect the pharmacologically active metabolites, risperidone and paliperidone, separately, while still not detecting the inactive metabolites, 7-hydroxyrisperidone and N-dealkylrisperidone. Antibodies may be generated that detect multiple ones of these drugs and/or metabolites, or antibodies may be generated that detect each separately (thus defining the antibody “specific binding” properties). An antibody specifically binds one or more compounds when its binding of the one or more compounds is equimolar or substantially equimolar.

Methods of producing such antibodies comprise inoculating a host with the conjugate described herein. Suitable hosts include, but are not limited to, mice, rats, hamsters, guinea pigs, rabbits, chickens, donkeys, horses, monkeys, chimpanzees, orangutans, gorillas, humans, and any species capable of mounting a mature immune response. The immunization procedures are well established in the art and are set forth in numerous treatises and publications including “The Immunoassay Handbook”, 2nd Edition, edited by David Wild (Nature Publishing Group, 2000) and the references cited therein.

Preferably, an immunogen embodying features of the present invention is administered to a host subject, e.g., an animal or human, in combination with an adjuvant. Suitable adjuvants include, but are not limited to, Freund's adjuvant, powdered aluminum hydroxide (alum), aluminum hydroxide together with Bordetella pertussis, and monophosphoryl lipid A-synthetic trehalose dicorynomycolate (MPL-TDM).

Typically, an immunogen or a combination of an immunogen and an adjuvant is injected into a mammalian host by one or multiple subcutaneous or intraperitoneal injections. Preferably, the immunization program is carried out over at least one week, and more preferably, over two or more weeks. Polyclonal antibodies produced in this manner can be isolated and purified utilizing methods well know in the art.

Monoclonal antibodies can be produced by the well-established hybridoma methods of Kohler and Milstein, e.g., Nature 256:495-497 (1975). Hybridoma methods typically involve immunizing a host or lymphocytes from a host, harvesting the monoclonal antibody secreting or having the potential to secrete lymphocytes, fusing the lymphocytes to immortalized cells, and selecting cells that secrete the desired monoclonal antibody.

A host can be immunized to elicit lymphocytes that produce or are capable of producing antibodies specific for an immunogen. Alternatively, the lymphocytes can be immunized in vitro. If human cells are desired, peripheral blood lymphocytes can be used, although spleen cells or lymphocytes from other mammalian sources are preferred.

The lymphocytes can be fused with an immortalized cell line to form hybridoma cells, a process which can be facilitated by the use of a fusing agent, e.g., polyethylene glycol. By way of illustration, mutant rodent, bovine, or human myeloma cells immortalized by transformation can be used. Substantially pure populations of hybridoma cells, as opposed to unfused immortalized cells, are preferred. Thus, following fusion, the cells can be grown in a suitable medium that inhibits the growh or survival of unfused, immortalized cells, for example, by using mutant myeloma cells that lack the enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT). In such an instance, hypoxanthine, aminopterin, and thymidine can be added to the medium (HAT medium) to prevent the growth of HGPRT-deficient cells while permitting hybridomas to grow.

Preferably, immortalized cells fuse efficiently, can be isolated from mixed populations by selection in a medium such as HAT, and support stable and high-level expression of antibody following fusion. Preferred immortalized cell lines include myeloma cell lines available from the American Type Culture Collection, Manassas, Va.

Because hybridoma cells typically secrete antibody extracellularly, the culture media can be assayed for the presence of monoclonal antibodies specific for the anti-psychotic drug. Immunoprecipitation of in vitro binding assays, for example, radiioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA), can be used to measure the binding specificity of monoclonal antibodies.

Monoclonal antibody-secreting hybridoma cells can be isolated as single clones by limiting dilution procedures and sub-cultured. Suitable culture media include, but are not limited to, Dulbecco's Modified Eagle's Medium, RPMI-1640, and polypeptide-free, polypeptide-reduced, or serum-free media, e.g., Ultra DOMA PF or HL-1, available from Biowhittaker, Walkersville, Md. Alternatively, the hybridoma cells can be grown in vivo as ascites.

Monoclonal antibodies can be isolated and/or purified from a culture medium or ascites fluid by conventional immunoglobulin (Ig) purification procedures including, but not limited to, polypeptide A-SEPHAROSE, hydroxylapatite chromatography, gel electrophoresis, dialysis, ammonium sulfate precipitation, and affinity chromatography.

Monoclonal antibodies can also be produced by recombinant methods such as are described in U.S. Pat. No. 4,166,452. DNA encoding monoclonal antibodies can be isolated and sequenced using conventional procedures, e.g., using oligonucleotide probes that specifically bind to murine heavy and light antibody chain genes, preferably to probe DNA isolated from monoclonal antibody hybridoma cells lines secreting antibodies specific for anti-psychotic drugs.

Antibody fragments which contain specific binding sites for the anti-psychotic drug may also be generated. Such fragments include, but are not limited to, the F(ab′)₂ fragments which can be produced by pepsin digestion of the antibody molecule and the Fab fragments which can be generated by reducing the disulfide bridges of the F(ab′)₂ fragments. Alternatively, Fab expression libraries may be constructed to allow rapid and easy identification of monoclonal Fab fragments with the desired specificity (Huse et al., Science 256:1270-1281 (1989)). Fab, Fv and ScFv antibody fragments can all be expressed in and secreted from Escherichia coli, allowing for the production of large amounts of these fragments. Alternatively, Fab′-SH fragments can be directly recovered from E. coli and chemically coupled to form F(ab′)₂ fragments (Carter et al., BioTechnology 10:163-167 (1992)). Other techniques for the production of antibody fragments are known to those skilled in the art. Single chain Fv fragments (scFv) are also envisioned (see U.S. Pat. Nos. 5,761,894 and 5,587,458). Fv and sFv fragments are the only species with intact combining sites that are devoid of constant regions; thus, they are likely to show reduced non-specific binding. The antibody fragment may also be a “linear antibody” e.g., as described in U.S. Pat. No. 5,642,870, for example. Such linear antibody fragments may be monospecific or bispecific.

Assay Kits and Devices

An assay kit (also referred to as a reagent kit) can also be provided comprising an antibody as described above. A representative reagent kit may comprise an antibody that binds to the anti-psychotic drug, paliperidone, a complex comprising an analog of an anti-psychotic drug or a derivative thereof coupled to a labeling moiety, and may optionally also comprise one or more calibrators comprising a known amount of an anti-psychotic drug or a related standard.

The phrase “assay kit” refers to an assembly of materials and reagents that is used in performing an assay. The reagents can be provided in packaged combination in the same or in separate containers, depending on their cross-reactivities and stabilities, and in liquid or in lyophilized form. The amounts and proportions of reagents provided in the kit can be selected so as to provide optimum results for a particular application. An assay kit embodying features of the present invention comprises antibodies which bind paliperidone. The kit may further comprise competitive binding partners of paliperidone and calibration and control materials.

The phrase “calibration and control material” refers to any standard or reference material containing a known amount of an analyte. A sample suspected of containing an analyte and the corresponding calibration material are assayed under similar conditions. The concentration of analyte is calculated by comparing the results obtained for the unknown specimen with the results obtained for the standard. This is commonly done by constructing a calibration curve.

Antibodies embodying features of the present invention can be included in a kit, container, pack, or dispenser together with instructions for their utilization. When the antibodies are supplied in a kit, the different components of the immunoassay may be packaged in separate containers and admixed prior to use. Such packaging of the components separately may permit long-term storage without substantially diminishing the functioning of the active components. Furthermore, reagents can be packaged under inert environments, e.g., under a positive pressure of nitrogen gas, argon gas, or the like, which is especially preferred for reagents that are sensitive to air and/or moisture.

Reagents included in kits embodying features of the present invention can be supplied in all manner of containers such that the activities of the different components are substantially preserved while the components themselves are not substantially adsorbed or altered by the materials of the container. Suitable containers include, but are not limited to, ampules, bottles, test tubes, vials, flasks, syringes, envelopes, e.g., foil-lined, and the like. The containers may be comprised of any suitable material including, but not limited to, glass, organic polymers, e.g., polycarbonate, polystyrene, polyethylene, etc., ceramic, metal, e.g., aluminum, metal alloys, e.g., steel, cork, and the like. In addition, the containers may comprise one or more sterile access ports, e.g., for access via a needle, such as may be provided by a septum. Preferred materials for septa include rubber and polytetrafluoroethylene of the type sold under the trade name TEFLON by DuPont (Wilmington, Del.). In addition, the containers may comprise two or more compartments separated by partitions or membranes that can be removed to allow mixing of the components.

Reagent kits embodying features of the present invention may also be supplied with instructional materials. Instructions may be printed, e.g., on paper and/or supplied in an electronically-readable medium. Alternatively, instructions may be provided by directing a user to an internet website, e.g., specified by the manufacturer or distributor of the kit and/or via electronic mail.

The antibody may also be provided as part of an assay device. Such assay devices include lateral flow assay devices. A common type of disposable lateral flow assay device includes a zone or area for receiving the liquid sample, a conjugate zone, and a reaction zone. These assay devices are commonly known as lateral flow test strips. They employ a porous material, e.g., nitrocellulose, defining a path for fluid flow capable of supporting capillary flow. Examples include those shown in U.S. Pat. Nos. 5,559,041, 5,714,389, 5,120,643, and 6,228,660 all of which are incorporated herein by reference in their entireties.

Another type of assay device is a non-porous assay device having projections to induce capillary flow. Examples of such assay devices include the open lateral flow device as disclosed in PCT International Publication Nos. WO 2003/103835, WO 2005/089082, WO 2005/118139, and WO 2006/137785, all of which are incorporated herein by reference in their entireties.

In a non-porous assay device, the assay device generally has at least one sample addition zone, at least one conjugate zone, at least one reaction zone, and at least one wicking zone. The zones form a flow path by which sample flows from the sample addition zone to the wicking zone. Also included are capture elements, such as antibodies, in the reaction zone, capable of binding to the analyte, optionally deposited on the device (such as by coating); and a labeled conjugate material also capable of participating in reactions that will enable determination of the concentration of the analyte, deposited on the device in the conjugate zone, wherein the labeled conjugate material carries a label for detection in the reaction zone. The conjugate material is dissolved as the sample flows through the conjugate zone forming a conjugate plume of dissolved labeled conjugate material and sample that flows downstream to the reaction zone. As the conjugate plume flows into the reaction zone, the conjugated material will be captured by the capture elements such as via a complex of conjugated material and analyte (as in a “sandwich” assay) or directly (as in a “competitive” assay). Unbound dissolved conjugate material will be swept past the reaction zone into the at least one wicking zone. Such devices can include projections or micropillars in the flow path.

An instrument such as that disclosed in US Patent Publication Nos. US20060289787A1 and US 20070231883A1, and U.S. Pat. Nos. 7,416,700 and 6,139,800, all of which are incorporated herein by reference in their entireties, is able to detect the bound conjugated material in the reaction zone. Common labels include fluorescent dyes that can be detected by instruments which excite the fluorescent dyes and incorporate a detector capable of detecting the fluorescent dyes.

Immunoassays

The antibodies thus produced can be used in immunoassays to recognize/bind to the anti-psychotic drug, thereby detecting the presence and/or amount of the drug in a patient sample. Preferably, the assay format is a competitive immunoassay format. Such an assay format and other assays are described, among other places, in Hampton et al. (Serological Methods, A Laboratory Manual, APS Press, St. Paul, Minn. 1990) and Maddox et al. (J. Exp. Med. 158:12111, 1983).

The term “analyte” refers to any substance or group of substances, the presence or amount of which is to be determined. Representative anti-psychotic drug analytes include, but are not limited to, risperidone, paliperidone, olanzapine, aripiprazole, and quetiapine.

The term “competitive binding partner” refers to a substance or group of substances, such as may be employed in a competitive immunoassay, which behave similarly to an analyte with respect to binding affinity to an antibody. Representative competitive binding partners include, but are not limited to, anti-psychotic drug derivatives and the like.

The term “detecting” when used with an analyte refers to any quantitative, semi-quantitative, or qualitative method as well as to all other methods for determining an analyte in general, and an anti-psychotic drug in particular. For example, a method that merely detects the presence or absence of an anti-psychotic drug in a sample lies within the scope of the present invention, as do methods that provide data as to the amount or concentration of the anti-psychotic drug in the sample. The terms “detecting”, “determining”, “identifying”, and the like are used synonymously herein, and all lie within the scope of the present invention.

A preferred embodiment of the subject invention is a competitive immunoassay wherein antibodies which bind the anti-psychotic drug, or the drug or competitive binding partner thereof, are attached to a solid support (such as the reaction zone in a lateral flow assay device) and labeled drug or competitive binding partner thereof, or labeled antibody, respectively, and a sample derived from the host are passed over the solid support and the amount of label detected attached to the solid support can be correlated to a quantity of drug in the sample.

Any sample that is suspected of containing an analyte, e.g., an anti-psychotic drug, can be analyzed in accordance with the methods of the presently preferred embodiments. The sample can be pretreated if desired and can be prepared in any convenient medium that does not interfere with the assay. Preferably, the sample comprises an aqueous medium such as a body fluid from a host, most preferably plasma or serum.

It is to be understood that all manner of immunoassays employing antibodies are contemplated for use in accordance with the presently preferred embodiments, including assays in which antibodies are bound to solid phases and assays in which antibodies are in liquid media. Methods of immunoassays that can be used to detect analytes using antibodies embodying features of the present invention include, but are not limited to, competitive (reagent limited) assays wherein labeled analyte (analyte analog) and analyte in a sample compete for antibodies and single-site immunometric assays wherein the antibody is labeled; and the like.

The present invention is further described by the following examples. The examples are provided solely to illustrate the invention by reference to specific embodiments. These exemplifications, while illustrating certain specific aspects of the invention, do not portray the limitations or circumscribe the scope of the disclosed invention.

All examples were carried out using standard techniques, which are well known and routine to those of skill in the art, except where otherwise described in detail. Routine molecular biology techniques of the following examples can be carried out as described in standard laboratory manuals, such as Sambrook et al., Molecular Cloning: A Laboratory Manual, 2nd Ed., Cold Spring Habor Laboratory Press, Cold Spring Harbor, N.Y. (1989).

Copending applications entitled “Haptens of Aripiprazole” (Attorney Docket No. PRD3265USPSP, U.S. Provisional Patent Appl. No. 61/691,450, filed Aug. 21, 2012), “Haptens of Olanzapine” (Attorney Docket No. PRD3266USPSP, U.S. Provisional Patent Appl. No. 61/691,454, filed Aug. 21, 2012), “Haptens of Paliperidone” (Attorney Docket No. PRD3267USPSP, U.S. Provisional Patent Appl. No. 61/691,459, filed Aug. 21, 2012), “Haptens of Quetiapine” (Attorney Docket No. PRD3268USPSP, U.S. Provisional Patent Appl. No. 61/691,462, filed Aug. 21, 2012), “Haptens of Risperidone and Paliperidone” (Attorney Docket No. PRD3269USPSP, U.S. Provisional Patent Appl. No. 61/691,469, filed Aug. 21, 2012), “Antibodies to Aripiprazole Haptens and Use Thereof” (Attorney Docket No. CDS5128USPSP, U.S. Provisional Patent Appl. No. 61/691,544, filed Aug. 21, 2012), “Antibodies to Olanzapine Haptens and Use Thereof” (Attorney Docket No. CDS5132USPSP, U.S. Provisional Patent Appl. No. 61/691,572, filed Aug. 21, 2012), “Antibodies to Quetiapine Haptens and Use Thereof” (Attorney Docket No. CDS5134USPSP, U.S. Provisional Patent Appl. No. 61/691,598, filed Aug. 21, 2012), “Antibodies to Risperidone Haptens and Use Thereof” (Attorney Docket No. CDS5130USPSP, U.S. Provisional Patent Appl. No. 61/691,615, filed Aug. 21, 2012), “Antibodies to Aripiprazole and Use Thereof” (Attorney Docket No. CDS5129USPSP, U.S. Provisional Patent Appl. No. 61/691,522, filed Aug. 21, 2012), “Antibodies to Olanzapine and Use Thereof” (Attorney Docket No. CDS5133USPSP, U.S. Provisional Patent Appl. No. 61/691,645, filed Aug. 21, 2012), “Antibodies to Paliperidone and Use Thereof” (Attorney Docket No. CDS5127USPSP, U.S. Provisional Patent Appl. No. 61/691,692, filed Aug. 21, 2012), “Antibodies to Quetiapine and Use Thereof” (Attorney Docket No. CDS5135USPSP, U.S. Provisional Patent Appl. No. 61/691,659, filed Aug. 21, 2012), “Antibodies to Risperidone and Use Thereof” (Attorney Docket No. CDS5131USPSP, U.S. Provisional Patent Appl. No. 61/691,675, filed Aug. 21, 2012), and “Antibodies to Risperidone and Use Thereof” (Attorney Docket No. CDS5145USPSP, U.S. Provisional Patent Appl. No. 61/790,880, filed Mar. 15, 2013) are all incorporated herein by reference in their entireties.

EXAMPLE 1 4-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6, 7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)-4-oxobutanoic acid

Paliperidone (10 g, 23.45 mmol) was dissolved in pyridine (100 mL) together with N,N-dimethyl-4-pyridinamine (0.5 g; 4.09 mmol) and succinic anhydride (18.3 g; 182.86 mmol). The mixture was stirred under an argon atmosphere for 4 h at 60° C. and for 48 h at room temperature. The reaction mixture was evaporated and dissolved in dichloromethane/methanol (100 mL/10 mL) and water (100 mL). The aqueous phase was extracted five times with dichloromethane/methanol (100 mL/10 mL). The organic layers were combined, dried over Na₂SO₄ and evaporated under vacuum. The residue was purified by silica gel chromatography (gradient elution with chloroform/ethanol 80/20 to 70/30). The product was dissolved in isopropanol (50 mL) and the resulting precipitate was filtered and washed with isopropanol (10 mL). The precipitate was dried in vacuo to give the title compound as a white solid. ESI-MS (M+1) 528. ¹H NMR: (DMSO-d₆, 360 MHz): δ ppm 1.75-2.75 (m, 23H), δ 3.5-4.0 (m, 3H), δ 5.74 (m, 1H), δ 7.28 (td, J=9.15, 2.20 Hz, 1H), δ 7.69 (dd, J=8.96, 2.01 Hz, 1H), δ 8.02 (dd, J=8.78, 5.12 Hz, 1H).

EXAMPLE 2 Step A 3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl 3-pivalamidopropanoate

A solution of Paliperidone (1.0 g, 2.34 mmol) in dichloromethane (20 mL) was treated with Boc-b-Ala-OH (443.65 mg, 2.34 mmol), dicyclohexylcarbodiimide (483.79 mg, 2.34 mmol) and N,N-dimethyl-4-pyridinamine (14.32 mg, 0.117 mmol). The reaction was stirred at room temperature under argon atmosphere. After 18 h, the reaction mixture was poured into an aqueous saturated sodium bicarbonate solution (20 mL) and the aqueous layer extracted with dichloromethane (three times 20 mL). The combined organic layers were dried over MgSO₄, filtered and concentrated. The residue was purified by silica gel chromatography (elution with dichloromethane/methanol (95/5) to give the title compound. ESI-MS (M+1) 598.

Step B 3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl 3-(3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)propanamido)propanoate

A solution of 3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl 3-pivalamidopropanoate, prepared as described in Step A, (901.5 mg, 1.15 mmol) in dichloromethane (20 mL) and trifluoroacetic acid (5.7 mL) was stirred for 1 h at room temperature. To this mixture was carefully added a solution of N-maleoyl-3-aminopropionic acid (233.8 mg, 1.38 mmol), diisopropylethylamine (13.94 mL), diethyl cyanophosphonate (306.57 μL, 1.81 mmol) and dichloromethane (2 mL). The reaction mixture was stirred for 1 h at room temperature under argon atmosphere. The reaction mixture was poured into water (20 mL) and the aqueous layer extracted with dichloromethane (three times 20 mL). The combined organic layers were dried over Na₂SO₄, filtered and concentrated. The crude mixture was purified on HPLC to give the title compound. ESI-MS (M+1) 649.

EXAMPLE 3 Step A N-(3-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)propyl)pivalamide

A solution of paliperidone (746.26 mg, 1.75 mmol) in THF (15 mL) was treated with 3-(Boc-amino)propyl bromide (500 mg, 2.10 mmol), 18-Crown-6 (231.25 mg, 0.874 mmol) and sodium hydride (60 w/w %, 139.97 mg, 3.5 mmol). The mixture was stirred at room temperature for 6 h. The solvent was removed under vacuum, dissolved in dichloromethane/water (50 mL/50 mL) and the aqueous layer extracted with dichloromethane (three times 50 mL). The combined organic layers were dried over Na₂SO₄, filtered and concentrated to give the title compound, which was used without further purification in the next step.

Step B 9-(3-aminopropoxy)-3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one

A solution of N-(3-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)propyl)pivalamide, prepared as described in Step A, (1.482 g, 2.54 mmol) in dichloromethane (10 mL) and trifluoroacetic acid (5 mL) was stirred for 1 h at room temperature. The reaction mixture was purified on a Porapak CX column to give the title compound which was used without further purification in the next step.

Step C 3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N-(3-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)propyl)propanamide

A solution of 9-(3-aminopropoxy)-3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one, prepared as described in Step B, (0.303 g, 0.627 mmol) in dichloromethane (5 mL), under argon, was treated with diisopropylethylamine (218.54 μL, 1.25 mmol), N-Maleoyl-3-aminopropionic acid (163.88 mg 0.940 mmol) and diethyl cyanophosphonate (159.19 μL, 0.940 mmol). After 18 h, the reaction mixture was poured into an aqueous saturated sodium bicarbonate solution (20 mL) and the aqueous layer extracted with dichloromethane (three times 20 mL). The combined organic layers were dried over Na₂SO₄, filtered and concentrated. The crude mixture was purified by HPLC to give the title compound. ESI-MS (M+1) 635.

EXAMPLE 4 6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoic acid

A solution of paliperidone (1.0 g, 2.34 mmol) in THF (15 mL), under argon, was treated with 18-Crown-6 (309.88 mg, 1.17 mmol), ethyl 6-bromohexanoate (628.76 μL, 3.52 mmol) and sodium hydride (60 w/w %, 937.80 mg, 23.45 mmol). After 18 h, the reaction mixture was poured into an aqueous saturated sodium bicarbonate solution (20 mL), and the aqueous layer was extracted with ethyl acetate (three times 20 mL). The aqueous layer was acidified with acetic acid and extracted with 2-methyl THF (three times 20 mL). The combined organic 2-methyl THF layers were dried over Na₂SO₄, filtered and concentrated. The residue was purified by HPLC to give the title compound. ESI-MS (M+1) 541. ¹H NMR: (CDCl₃, 360 MHz): δ ppm 1.35-2.00 (m, 11H), δ 2.10-2.30 (m, 8H), δ 2.40-2.80 (m, 8H), δ 3.20-4.00 (m, 5H), δ 4.24-4.30 (m, 1H), δ 7.07 (td, J=8.97, 1.83 Hz, 1H), δ 7.24 (d, J=1.83 Hz, 1H), δ 7.76 (dd, J=8.60, 4.94 Hz, 1H).

EXAMPLE 5 Step A tert-butyl 4-(6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoyl)piperazine-1-carboxylate

A solution of Example 4 (200 mg, 0.37 mmol) in dichloromethane (10 mL), under argon, was treated with N-t-butoxycarbonylpiperazine (89.57 mg, 0.48 mmol) and diisopropylethylamine (77.42 μL, 0.44 mmol). To the stirring solution, diethyl cyanophosphonate (72.06 μL, 0.43 mmol) was added. After stirring for two hours at room temperature, the reaction mixture was poured into water (20 mL) and the aqueous layer extracted with dichloromethane (three times 20 mL). The combined organic layers were dried over Na₂SO₄, filtered and concentrated. The crude mixture was used without further purification in the next step. (408 mg, ESI-MS (M+1) 709)

Step B 3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-9-((6-oxo-6-(piperazin-1-yl)hexyl)oxy)-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one

A solution of tert-butyl 4-(6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoyl)piperazine-1-carboxylate, prepared as described in Step A, (408 mg, 0.58 mmol) in dichloromethane (5 mL), under argon, was treated with trifluoroacetic acid (435.62 μL, 5.8 mmol). After stirring for 72 h at room temperature, the reaction mixture was poured into an aqueous saturated sodium bicarbonate solution (5 mL), and the aqueous layer was extracted with dichloromethane (three times 5 mL). The combined organic layers were dried over Na₂SO₄, filtered and concentrated. The crude product was used in the next step without further purification. (ESI-MS (M+1) 609)

Step C 4-(4-(6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoyl)piperazin-1-yl)-4-oxobutanoic acid

A solution of 3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-9-((6-oxo-6-(piperazin-1-yl)hexyl)oxy)-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one, prepared as described in Step B, (239 mg, 0.39 mmol) in dichloromethane (5 mL), under argon, was treated with succinic anhydride (43.15 mg, 0.43 mmol) and diisopropylethylamine (68.35 μL, 0.39 mmol). After stirring for 2 h at room temperature, the reaction mixture was poured into water (5 mL), and the aqueous layer was extracted with dichloromethane/methanol (95/5, three times 5 mL). The combined organic layers were dried over Na₂SO₄, filtered and concentrated. The residue was purified by HPLC and triturated with diisopropylether, to give the title compound. (ESI-MS (M+1) 709); ¹H NMR: (CDCl₃, 360 MHz): δ ppm 1.10-2.80 (m, 31H), δ 3.20-4.00 (m, 13H), δ 4.24-4.30 (m, 1H), δ 7.07 (td, J=8.97, 1.83 Hz, 1H), δ 7.24 (d, J=1.83 Hz, 1H), δ 7.76 (dd, J=8.60, 4.94 Hz, 1H)

EXAMPLE 6 3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N-(3-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)propyl)propanamide—keyhole limpet hemocyanin—conjugate

To a 4.22 mL solution of keyhole limpet hemocyanin (KLH, 18.0 mg, 0.18 μmoles) in 100 mM phosphate buffer, 0.46M sodium chloride, pH 7.4 was added 83.2 μL of a DMF solution of N-succinimidyl-S-acetylthioacetate (SATA, 25 mg/mL, 2.1 mg, 9.0 μmoles). The resulting solution was incubated at 20° C. for 1 hour on a roller mixer. The reaction was purified on a Sephadex G-25 column using 100 mM phosphate buffer, 0.46M sodium chloride, 5 mM EDTA, pH 6.0. To 9.37 mL of KLH-SATA (17.1 mg, 0.171 μmoles) was added 937 μL of 2.5M Hydroxylamine, 50 mM EDTA, pH 7.0. The resulting solution was incubated at 20° C. for 40 minutes on a roller mixer. The reaction was used as such in conjugation reaction with maleimide-activated hapten.

To the KLH-SH from step 1 (10.3 mL, 0.171 μmoles) was added 770 μL of a DMF solution of 3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N-(3-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)propyl)propanamide (prepared as described in Example 3, 10 mg/mL, 12.1 μmoles). The resulting cloudy mixture was incubated for 4 hours at 20° C. on a roller mixer. The reaction was filtered through a 0.2 μm syringe filter then purified on a Sephadex G-25 column using 100 mM phosphate buffer, 0.46M sodium chloride, at pH 7.4.

EXAMPLE 7 6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoic acid—bovine thyroglobulin—conjugate

A solution of 6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6, 7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoic acid (prepared as described in Example 4, 5.0 mg, 9.3 μmoles), N-hydroxysuccinimide (NHS, 3.9 mg, 34.2 μmoles) and N,N-dicyclohexylcarbodiimide (DCC, 7.1 mg, 34.2 μmoles) in 300 μL of DMF and 3 μL tributylamine was allowed to stir for 18 hours at 20° C. An 30 μL aliquot (30 μL, 9.3 mol) of the resultant solution was added to 1.52 mL of a solution of bovine thyroglobulin (BTG, 7.6 mg, 0.011 μmoles) in 100 mM phosphate buffer pH 7.5. The resulting cloudy mixture was incubated at 20° C. for 3 hours on a roller mixer. The reaction was filtered through a 0.45 μm syringe filter, followed by purification on a Sephadex G-25 column using 100 mM phosphate buffer, 0.14M sodium chloride, at pH 7.4.

EXAMPLE 8 4-(4-(6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoyl)piperazin-1-yl)-4-oxobutanoic acid—keyhole limpet hemocyanin—conjugate

A solution of 4-(4-(6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6, 7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoyl)piperazin-1-yl)-4-oxobutanoic acid (prepared as described in example 5, 10.6 mg, 15.0 μmoles), N-hydroxysuccinimide (NHS, 6.4 mg, 55.5 μmoles) and N,N-dicyclohexylcarbodiimide (DCC, 11.5 mg, 55.5 μmoles) in 400 μL of DMF and 4 μL of tributylamine was allowed to stir for 18 hours at 20° C. An 81 μL aliquot (3.0 μmoles) of the resulting solution was added to 2.75 mL of a solution of keyhole limpet hemocyanin (KLH, 12.0 mg, 0.12 μmoles) in 100 mM phosphate buffer, 0.46M sodium chloride, at pH 7.4. The resulting cloudy mixture was incubated at 20° C. for 2.5 hours on a roller mixer. The reaction was filtered through a 0.45 μm syringe filter then purified on a Sephadex G-25 column using 100 mM phosphate buffer, 0.46M sodium chloride, at pH 7.4.

EXAMPLE 9 4-(4-(6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6, 7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoyl)piperazin-1-yl)-4-oxobutanoic acid—bovine thyroglobulin—conjugate

A solution of 4-(4-(6-((3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)oxy)hexanoyl)piperazin-1-yl)-4-oxobutanoic acid (prepared as described in example 5, 17.1 mg, 24.1 μmoles), N-hydroxysuccinimide (NHS, 10.3 mg, 89.3 μmoles) and N,N-dicyclohexylcarbodiimide (DCC, 18.4 mg, 89.3 μmoles) in 600 μL of DMF and 6 μL of tributylamine was allowed to stir for 18 hours at 20° C. A 462 μL aliquot (18.4 μmoles) of the resulting solution was added to 3.0 mL of a solution of bovine thyroglobulin (BTG 15.0 mg, 0.023 μmoles) in 100 mM of pH 7.5 phosphate buffer. The resulting cloudy mixture was incubated at 20° C. for 2.5 hours on a roller mixer. The reaction was filtered through a 0.45 μm syringe filter then purified on a Sephadex G-25 column using 100 mM phosphate buffer, 0.14 M sodium chloride, at pH 7.4.

EXAMPLE 10 Competitive Immunoassays for Risperidone/Paliperidone and Multiplex Competitive Immunoassay for Aripiprazole, Olanzapine, Quetiapine, and Risperidone/Paliperidone

Following a series of immunizations with paliperidone/risperidone immunogens, mouse tail bleeds were tested for reactivity using an ELISA. Hybridoma supernatants were also tested, and the ELISA data shown in Tables 8 and 9 below shows reactivity of several hybridomas (fusion partner was NSO cells). As shown in Table 9, reactivity of hybridomas 2A5 and 5G11 was seen.

After clones were identified via ELISA reactivity, competition ELISAs were run to approximate affinity and cross-reactivity with similar compounds. FIGS. 1 and 2 show the ELISA cross-reactivity results from hybridoma subclone 5_9. Data shows reactivity to risperidone, as well as its metabolites paliperidone and 7-hydroxyrisperidone.

Supernatants were also tested by competition ELISA to determine if the signals were specific to either risperidone or paliperidone. FIG. 3 shows the results from hybridoma subclone 2A5. Data shows reactivity to both risperidone and paliperidone.

FIG. 4 shows the competitive immunoassay format used on a lateral flow assay device in which the capture antibody, risperidone/paliperidone clone 5-9, was deposited on a chip along with a detection conjugate consisting of risperidone conjugated to a fluorophore. In this competitive format as show in FIG. 4, a low level of analyte (paliperidone) results in high signal, whereas a high level of analyte (paliperidone) results in low signal. The amount of paliperidone in the sample can be calculated from the loss of fluorescence compared to a control sample with no drug present. A typical dose response curve generated with risperidone/paliperidone clone 5-9 is shown in FIG. 5.

FIG. 6 shows the chip design of a lateral flow assay device according to one embodiment of the subject invention. The device includes a zone or area for receiving the sample, a conjugate zone (which contains desired labeled competitive binding partner(s)), and a reaction zone (eight areas within the reaction zone are indicated; each area can contain a separate desired antibody). Sample flows from the sample zone through the conjugate zone and to the reaction zone.

FIGS. 7-10 show typical dose response curves for an aripiprazole positive control (sample containing aripiprazole) generated with antibody 5C7 deposited in reaction zone 2 and a labeled aripiprazole competitive binding partner in the conjugate zone (FIG. 7), an olanzapine positive control (sample containing olanzapine) generated with antibody 4G9-1 deposited in reaction zone 4 and a labeled olanzapine competitive binding partner in the conjugate zone (FIG. 8), a quetiapine positive control (sample containing quetiapine) generated with antibody 11 deposited in reaction zone 6 and a labeled quetiapine competitive binding partner in the conjugate zone (FIG. 9), and a risperidone positive control (sample containing risperidone) generated with antibody 5-9 deposited in reaction zone 8 and a labeled risperidone competitive binding partner in the conjugate zone (FIG. 10). The labeled competitive binding partners in the conjugate zone compete with the drugs present in the samples for binding to the antibodies. The amount of label is detected and is an indication of the amount of drug present in the sample (the amount of signal being inversely proportional to the amount of drug in the sample—see FIG. 4).

In order to confirm that conjugates of labeled competitive binding partners do not bind to antibodies deposited in the reaction zones, negative controls were conducted by using samples containing no drugs. Referring to Table 10, a sample containing no aripiprazole is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled olanzapine, labeled quetiapine, and labeled risperidone, but no labeled aripiprazole) and to the reaction zone. The reaction zone again contains aripiprazole antibody (5C7) in reaction zone 2. Table 10 below shows the results, confirming that there is no dose response and the olanzapine, quetiapine, and risperidone conjugates that move by capillary action through the reaction zone do not bind to the aripiprazole antibody.

Referring to Table 11, a sample containing no olanzapine is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole, labeled quetiapine, and labeled risperidone, but no labeled olanzapine) and to the reaction zone. The reaction zone again contains olanzapine antibody (4G9-1) in reaction zone 4. Table 11 below shows the results, confirming that there is no dose response and the aripiprazole, quetiapine, and risperidone conjugates that move by capillary action through the reaction zone do not bind to the olanzapine antibody.

Referring to Table 12, a sample containing no quetiapine is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole, labeled olanzapine, and labeled risperidone, but no labeled quetiapine) and to the reaction zone. The reaction zone again contains quetiapine antibody (11) in reaction zone 6. Table 12 below shows the results, confirming that there is no dose response and the aripiprazole, olanzapine, and risperidone conjugates that move by capillary action through the reaction zone do not bind to the quetiapine antibody.

Referring to Table 13, a sample containing no risperidone is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole, labeled olanzapine, and labeled quetiapine, but no labeled risperidone) and to the reaction zone. The reaction zone again contains risperidone antibody (5-9) in reaction zone 8. Table 13 below shows the results, confirming that there is no dose response and the aripiprazole, olanzapine, and quetiapine conjugates that move by capillary action through the reaction zone do not bind to the risperidone antibody.

In order to confirm that conjugates of labeled competitive binding partners bind only to their respective antibodies deposited in the reaction zones, additional negative controls were conducted by again using samples containing no drugs. Referring to Table 14, a sample containing no aripiprazole is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole) and to the reaction zone. The reaction zone again contains aripiprazole antibody (5C7) in reaction zone 2, as well as olanzapine antibody (4G9-1) in reaction zone 4, quetiapine antibody (11) in reaction zone 6, and risperidone antibody (5-9) in reaction zone 8. Table 14 below shows the results, confirming that there is no dose response except to the aripiprazole antibody 5C7 (in reaction zone 2).

Referring to Table 15, a sample containing no olanzapine is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled olanzapine) and to the reaction zone. The reaction zone again contains aripiprazole antibody (5C7) in reaction zone 2, as well as olanzapine antibody (4G9-1) in reaction zone 4, quetiapine antibody (11) in reaction zone 6, and risperidone antibody (5-9) in reaction zone 8. Table 15 below shows the results, confirming that there is no dose response except to the olanzapine antibody 4G9-1 (in reaction zone 4).

Referring to Table 16, a sample containing no quetiapine is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled quetiapine) and to the reaction zone. The reaction zone again contains aripiprazole antibody (5C7) in reaction zone 2, as well as olanzapine antibody (4G9-1) in reaction zone 4, quetiapine antibody (11) in reaction zone 6, and risperidone antibody (5-9) in reaction zone 8. Table 16 below shows the results, confirming that there is no dose response except to the quetiapine antibody 11 (in reaction zone 6).

Referring to Table 17, a sample containing no risperidone is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled risperidone) and to the reaction zone. The reaction zone again contains aripiprazole antibody (5C7) in reaction zone 2, as well as olanzapine antibody (4G9-1) in reaction zone 4, quetiapine antibody (11) in reaction zone 6, and risperidone antibody (5-9) in reaction zone 8. Table 17 below shows the results, confirming that there is no dose response except to the risperidone antibody 5-9 (in reaction zone 8).

The results shown above confirm that conjugates of labeled competitive binding partners bind only to their respective antibodies in the reaction zone.

FIGS. 11-14 show typical dose response curves in specific antibody reaction zones, and proof of dose response low/high concentration for each specific assay in the presence of other conjugates. In FIG. 11, a sample containing aripiprazole is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole, labeled olanzapine, labeled quetiapine, and labeled risperidone) and to the reaction zone. The reaction zone again contains aripiprazole antibody (5C7) in reaction zone 2. A typical dose response curve was generated as is shown in FIG. 11 only for aripiprazole, and not for olanzapine, quetiapine, or risperidone.

In FIG. 12, a sample containing olanzapine is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole, labeled olanzapine, labeled quetiapine, and labeled risperidone) and to the reaction zone. The reaction zone again contains olanzapine antibody (4G9-1) in reaction zone 4. A typical dose response curve was generated as is shown in FIG. 12 only for olanzapine, and not for aripiprazole, quetiapine, or risperidone.

In FIG. 13, a sample containing quetiapine is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole, labeled olanzapine, labeled quetiapine, and labeled risperidone) and to the reaction zone. The reaction zone again contains quetiapine antibody (11) in reaction zone 6. A typical dose response curve was generated as is shown in FIG. 13 only for quetiapine, and not for aripiprazole, olanzapine, or risperidone.

In FIG. 14, a sample containing risperidone is deposited in the sample zone and moves by capillary action through the conjugate zone (this time containing labeled aripiprazole, labeled olanzapine, labeled quetiapine, and labeled risperidone) and to the reaction zone. The reaction zone again contains risperidone antibody (5-9) in reaction zone 8. A typical dose response curve was generated as is shown in FIG. 14 only for risperidone, and not for aripiprazole, olanzapine, or quetiapine.

FIGS. 15-18 show typical dose response curves for each assay in the presence of other conjugates and antibodies. In FIG. 15, a sample containing aripiprazole is deposited in the sample zone and moves by capillary action through the conjugate zone (again containing labeled aripiprazole, labeled olanzapine, labeled quetiapine, and labeled risperidone) and to the reaction zone. The reaction zone again contains aripiprazole antibody (5C7) in reaction zone 2, as well as olanzapine antibody (4G9-1) in reaction zone 4, quetiapine antibody (11) in reaction zone 6, and risperidone antibody (5-9) in reaction zone 8. A typical dose response curve was generated for aripiprazole, as is shown in FIG. 15. When a sample containing olanzapine was deposited in the sample zone of this chip, a typical dose response curve was generated for olanzapine as shown in FIG. 16. When a sample containing quetiapine was deposited in the sample zone of this chip, a typical dose response curve for quetiapine was generated as shown in FIG. 17. When a sample containing risperidone was deposited in the sample zone of this chip, a typical dose response curve for risperidone was generated as shown in FIG. 18.

FIGS. 19-22 show comparisons of dose response curves generated as positive controls (FIGS. 7-10) to dose response curves generated in the multiplex format (FIGS. 15-18). The comparison for aripiprazole is shown in FIG. 19; for olanzapine in FIG. 20; for quetiapine in FIG. 21; and for risperidone in FIG. 22. These figures show that the positive control curves are similar to the multiplex curves.

These data show that a lateral flow assay device of the subject invention can be used to detect multiple anti-psychotic drugs using a single sample from a patient on one portable, point-of-care device. 

What is claimed is:
 1. A method of producing an antibody or a binding fragment thereof which binds to paliperidone, the method comprising: (i) selecting a host for antibody production; and (ii) inoculating the host with a conjugate of a compound of Formula I and an immunogenic carrier, wherein the host produces an antibody which binds to paliperidone,

wherein L¹ is OC(O)(CH₂)_(n), or O(CH₂)_(n); wherein n is 2 or 3; L² is NHC(O),

or absent; L³ is (CH₂)mCO₂H, or

wherein m is 0, 1, 2, or 3; provided that m may only be 0 if L² is absent, and further provided that when L² is absent L³ is


2. A method of producing a hybridoma cell line capable of producing a monoclonal antibody which binds to paliperidone, the method comprising: (i) selecting a host for antibody production; (ii) inoculating the host with a conjugate of a compound of Formula I and an immunogenic carrier; (iii) fusing a cell line from said inoculated host with a continuously dividing cell to create a fused cell capable of producing a monoclonal antibody which binds to paliperidone; and (iv) cloning the fused cell so as to obtain a hybridoma cell line,

wherein L¹ is OC(O)(CH₂)_(n), or O(CH₂)_(n); wherein n is 2 or 3; L² is NHC(O),

or absent; L³ is (CH₂)_(m)CO₂H, or

wherein m is 0, 1, 2, 3; provided that m may only be 0 if L² is absent, and further provided that when L² is absent L³ is


3. The method of claim 1, wherein the immunogenic carrier is a protein.
 4. The method of claim 3, wherein the protein is keyhole limpet hemocyanin, bovine thyroglobulin, or ovalbumin.
 5. The method of claim 2, wherein the immunogenic carrier is a protein.
 6. The method of claim 5, wherein the protein is keyhole limpet hemocyanin, bovine thyroglobulin, or ovalbumin.
 7. The method of claim 1, wherein the antibody binding fragment is selected from the group of fragments consisting of Fv, F(ab′), F(ab′)2, scFv, minibody and diabody fragments.
 8. The method of claim 1, wherein the antibody is a monoclonal antibody. 